On a workday morning, who is forcefully "booting up" with willpower? While mentally shouting "Wake up, wake up" to yourself, you silently hit the snooze button on the first alarm; the second one rings, you hit snooze again; the third one... Forget it, just 5 more minutes. So, your phone screen is filled with a dense list of "6:40, 6:45, 6:50, 6:55"... That's not just an alarm, it's a grand "wake-up defense battle."
Some say that not setting an alarm is self-indulgence; one alarm can't wake the soul, requiring a "fatal continuous call" for a continuous "blast." According to a study[1] in Scientific Reports covering 3 million sleep periods of big data, human obsession with "snoozing for a bit longer" has reached collective frenzy: over half of all sleep periods end with "snooze alarms," with an average of 2.4 snoozes per person per day, totaling about 10.8 minutes of snoozing. What seems like simply "lying in bed" is, in fact, a universally unified morning "performance art."
But here's the question: Is repeated snoozing, this intermittent morning sleep, truly healthy?
Many believe that snoozing is a sign of unhealthiness. However, a study[2] by a Swedish research team published in the Journal of Sleep Research brought a surprising new finding: moderate snoozing, for those "professional lie-in enthusiasts," might actually be a clever way to combat "sleep inertia"—not only does it not significantly impair daytime cognition and mood, but it can even, to some extent, enhance alertness and reaction time upon waking.
Swedish Study:
Snoozing Leads to "Painless" Waking
This study was divided into two parts, systematically investigating the common but rarely deeply explored phenomenon of "snooze alarms" from both behavioral and physiological perspectives.
The research team first launched a large-scale online survey, collecting sleep and awakening habit data from 1732 adults. The answer could almost be summarized in one word: "snooze." Most people reported needing to "snooze" in the morning, and setting multiple alarms was standard practice. The reasons for snoozing varied—too tired to get up, wanting to wake up more comfortably, needing a bit of mental preparation to ease into the day.
But a survey alone wasn't enough; the research team decided to "dig deeper": Does snoozing actually have an impact? Does it make one more alert, or more muddled?
Why this design? Because the researchers wanted to explore a phenomenon called sleep inertia. Simply put, when a person first wakes up, their brain isn't immediately fully awake; they might experience a brief period of "daze," such as slow reactions, mental confusion, decreased memory...
To clarify whether snoozing affects this process, researchers invited participants to complete a series of cognitive tests immediately upon waking and again 40 minutes later.
Overall, participants in the snooze group were less likely to be woken by an alarm from deep sleep (N3 stage). Generally, being forcibly woken from deep sleep can induce "sleep inertia," while snoozing provides a "gradual awakening" process.
Moreover, at the very moment of waking, the snooze group's overall cognitive performance was actually superior! For example, their arithmetic calculation speed was faster; and when faced with sudden distracting information, their reactions were more agile. These findings suggest that snoozing may, to some extent, alleviate sleep inertia, helping the brain transition more smoothly from a sleeping state to an awake state.
Additionally, in the episodic memory task, the snooze group performed significantly better than the "one-alarm wake-up" group immediately upon waking, indicating that a brief "extra moment of sleep" might aid information retrieval and memory function activation. Although this advantage gradually disappeared after 40 minutes, with both groups' performance converging, this precisely illustrates a key point: the positive effects of snoozing are mainly concentrated in the "critical early awakening phase," potentially offering help to individuals who need to immediately tackle tasks (such as getting up early for work, driving, etc.).
In fact, the brain has a "startup program." One of the key buttons in this program is a hormone called cortisol. Cortisol is like the body's "morning stimulant"—it rapidly increases shortly after waking, helping us switch from a groggy state to an alert mode of "I need to go to work/school/catch the subway." This hormonal change process is also known as the cortisol awakening response (CAR).
So, the question arises: Will snoozing, the habit of hitting the alarm and staying in bed a bit longer in the morning, disrupt this "awakening system"?
To answer this question, the research team measured participants' salivary cortisol levels in the experiment to see if snoozing interfered with CAR.
The results showed that whether in the one-alarm wake-up group or the snooze group, the cortisol secretion rhythm of these participants was not disturbed. This means that the body continued to "start up" according to its familiar rhythm, without being thrown into disarray by "snoozing."
Of course, the researchers were still not satisfied and continued to ask: Will snoozing affect mood? Will it make people feel unclear-headed all day?
The answer is still: No.
There were no significant differences between the snooze group and the direct wake-up group in terms of subjective alertness, mood ratings, or daytime mental performance. This indicates that moderate snoozing neither makes one lethargic all day nor worsens one's mood.
In summary, this study suggests that for people who inherently have a habit of snoozing, moderate snoozing may help alleviate sleep inertia, improve cognitive function upon waking, and not cause significant negative effects on mood and cognition.
Japanese Study:
Snoozing is Not a "Buffer," But Worsens Sleep Inertia
However, science is never about "one standard answer." Just as we were applauding the potential benefits of "moderate snoozing," another study[3] from a Japanese team presented a completely different conclusion.
This study found that "snooze alarms" might not be as gentle as imagined; instead, they might make it harder for people to truly wake up. Although using snooze alarms had no significant impact on overall sleep quality, people who used snooze alarms were more likely to fall into a "half-awake, half-asleep" state during the last 20 minutes before waking, meaning their brain waves showed shallow N1 stage sleep, with frequent brief awakenings that were interrupted.
So, why do so many people still insist on "snoozing" every day?
As for the motivation behind "snoozing," participants' answers also revealed some "mysteries" at the psychological level.
Overall, using snooze alarms did not cause a sharp decline in overall sleep quality throughout the night, but its "damaging power" was concentrated in the most critical 20 minutes before waking—precisely the period when we recharge for the morning.
Focusing on this "golden" 20-minute period, the data revealed multiple "reverse effects" of snooze alarms.
This means that snoozing didn't actually "add more sleep," but rather directly squeezed out actual rest time.
Even worse, this time, which should have been for proper rest, became particularly inefficient. Participants in the snooze group showed a significant decrease in sleep efficiency, longer waking times, and a marked increase in the light sleep stage (N1). This state could be described as "neither fully awake nor fully asleep," offering neither relief from fatigue nor invigoration.
What best reveals the "interfering nature" of snooze alarms is their severe disruption of awakening frequency and sleep stages.
This indicates that this morning sleep period was completely fragmented, like a movie constantly interrupted, preventing one from ever fully immersing in it.
So, would these sleep structural disruptions directly affect our reaction ability after waking? The study also sought answers by measuring auditory reaction time and accuracy. The results showed: At the moment of waking, there was no significant difference between the two groups, meaning that snoozing or not had little impact on immediate "wake-up" reaction time.
But the problem emerged "some time after waking."
In other words, while others had already "loaded" and were ready to start a new day, the snooze party was still "stuck spinning," with the nervous system's awakening process significantly lagging.
From a subjective experience perspective, although snooze alarms did not significantly exacerbate pre-sleep anxiety or morning sleepiness, participants did report a stronger sense of "sleep fragmentation" and "difficulty maintaining sleep." Physiologically, the awakening rhythm of the autonomic nervous system was also disrupted by snoozing, with physiological activity slowly increasing after waking, and the body remaining immersed in a vague sleep inertia.
In summary, this study suggests that, compared to a single wake-up, snooze alarms may exacerbate sleep inertia due to repeated forced awakenings.
Snooze Showdown,
Why Do Conclusions Contradict?
These two studies on "snoozing," at first glance, reach diametrically opposed conclusions. Which one is closer to the truth? To unravel the mystery, one must examine their respective "tactical deployments" in the "snooze battlefield."
Study[2] took the "gentle awakening" approach: each snooze lasted 9 to 10 minutes, with perfect timing. This duration was enough for participants to re-enter a slightly deeper N2 sleep without slipping into the harder-to-wake N3 stage, cleverly avoiding the nightmare combination of "deep sleep + sudden alarm." Because the awakening was gentler, cognitive performance after waking was better.
In contrast, Study[3]'s strategy seemed more aggressive. It subjected participants to an alarm "disturbance" every 5 minutes, waking them 4 times within a short 20 minutes. Participants' sleep stages remained in shallow N1, never getting a chance to enter restorative sleep stages. Ultimately, their reaction times significantly slowed, becoming a typical case of "neither sleeping well nor waking well."
However, the differences in results were not solely due to the "duration" of snoozing; the participants' inherent "sleep foundation" also played a significant role. Study[2] recruited "veteran lie-in enthusiasts," who had long been accustomed to intermittent awakenings, and whose bodies had gradually adapted to this fragmented sleep. They might have adjusted their sleep structure, such as compressing the N3 stage, to reduce the impact of sudden awakenings, thereby mitigating sleep inertia and allowing them to wake up more smoothly with better performance.
Conversely, the participants in Study[3] were different; most of them used alarms to "prevent oversleeping"—in essence, they were driven by anxiety. Such individuals often don't get enough sleep to begin with, and coupled with strong waking-up pressure, their minds are under continuous tension. Anxiety not only makes it easy to sleep lightly but also, when combined with frequent sleep interruptions, can lead to a vicious cycle of "anxiety—light sleep—more anxiety," thereby exacerbating post-waking fatigue and cognitive sluggishness.
From this perspective, whether a "snooze alarm" is a gentle remedy for those who struggle to wake up or a hidden killer of sleep quality is not a one-size-fits-all answer. It depends on what kind of "snoozer" we are and what kind of snoozing strategy we employ. Whether and how to "snooze" is indeed a nuanced art that requires rhythm and self-awareness.
It should also be noted that Study[2] only investigated the effects of 30 minutes of snoozing, and the effects of longer or shorter snoozing durations are still unclear; Study[3] had a smaller sample size, which may limit the power of statistical analysis, and its results may be difficult to generalize to other age groups or occupational populations.
References:
[1]Robbins, R., Sääf, D., Weaver, M.D. et al. Snooze alarm use in a global population of smartphone users. Sci Rep15, 16942 (2025). https://doi.org/10.1038/s41598-025-99563-y
[2]Sundelin T, Landry S, Axelsson J. Is snoozing losing? Why intermittent morning alarms are used and how they affect sleep, cognition, cortisol, and mood. J Sleep Res. 2024 May;33(3):e14054. doi: 10.1111/jsr.14054. Epub 2023 Oct 17. PMID: 37849039.
[3]Ogawa K, KaizumaUeyama E, Hayashi M. Effects of using a snooze alarm on sleep inertia after morning awakening. J Physiol Anthropol. 2022 Dec 31;41(1):43. doi: 10.1186/s40101-022-00317-w. PMID: 36587230; PMCID: PMC9804954.
Written by | Mubai
Edited by | Mubai
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